While riding New York City’s L Train, I spotted this tattoo on an anonymous Williamsburg-bound hipster. I only had a few moments to chat with him as my stop was coming up, but he claims it is a full schematic for a guitar amplifier circuit. It heartens me to think that a piece of engineering ephemera has elevated itself to hipster tattoo art, but another part of me is dismayed. After further inquiry, it turns out the tattoo owner is a musician and actually has no clue what any of those strange symbols mean on his arm.

The first night I met my wife, I noticed the schematic symbol for A/C on her wrist and thought she might be a keeper (especially after finding “soldering” listed under her hobbies on MySpace and realizing that she could cogently explain the difference between alternating and direct current).

Have schematic tattoos become the hip ink du jour? Are they indelible reminders for the rebuilding of a post-apocalyptic society, or just another tattoo fad like tribal markings or cryptic characters in foreign languages?

In addition to being an online editor for MAKE Magazine, Michael Colombo works in fabrication, electronics, sound design, music production and performance (Yes. All that.) In the past he has also been a childrens’ educator and entertainer, and holds a Masters degree from NYU’s Interactive Telecommunications Program.

I’m no expert, but that is the weirdest tube amp schematic I’ve ever seen. The main things that I notice: there are no bypass caps on the preamp cathodes, and there are no volume or tone controls. Perhaps it serves a specific purpose that I just don’t see?

I think that tattoos of a symbol is cool as a statement of interest. I don’t like the whole schematic tattoo idea, but I can’t really say too much since the only ink on me is if I miss when recapping a pen. :)

http://www.facebook.com/profile.php?id=694496665 Susan Jones

Putting something out there and having no idea what it means or is…. it’s copy and paste, the hallmark of our times. At least know waht you’re copying…

http://pulse.yahoo.com/_IXHTKZLA2HDRWR5JBGBIAEPQ4Q Abend Haeker

“the tattoo owner … has no clue what any of those strange symbols mean on his arm”

So it’s the new “getting ink of Chinese characters without running them by someone fluent in Chinese”?

Also, where are the part values? I mean, I can probably guess some of the grid bias stuff, but really…

Anonymous

It would be more interesting if the ink was conductive. Maybe then you could tattoo on actual working circuits.

“A miniature diagnostic device with the mechanical properties of skin
was developed by engineers at the University of Illinois. It can be
mounted directly to the wrist or anywhere on the human body for EMG and
other measurements. The circuit almost becomes part of the skin as it bends, wrinkles, and stretches.

Components in the circuit include sensors, LEDs, transistors, radio
frequency capacitors, wireless antennas, and conductive coils and solar
cells. ”

Put pickup coils over specific nerve points, as done with advanced prosthetic devices, and you can control external devices, gesture recognition, etc.

Anonymous

It looks like a tube version of an op-amp. The first and second dual tube are set up as a long tail pair with the second dual being used as a phase inverter to drive the ultra linear output tubes. The first dual tube is a little odd in the way it’s set up. Normally a single ended amp (12AX7 type) is used as the input with the system ground. Also, there isn’t enough tubes on the front end for amplification of a guitar signal. The first dual is set up as an op amp (with inverting and non-inverting inputs) to cancel out any common mode ground signals. I believe this amp design was used as an add on for an existing pre-amp/mixer, which is why it doesn’t have any tone controls. The controls (including the volume) would be in the pre-amp/mixer.

johngineer

“it turns out the tattoo owner is a musician and actually has no clue what any of those strange symbols mean on his arm.”

That describes at least 90% of the ridership on the L-train at any given time. :)

johngineer

“it turns out the tattoo owner is a musician and actually has no clue what any of those strange symbols mean on his arm.”

That describes at least 90% of the ridership on the L-train at any given time. :)

johngineer

“it turns out the tattoo owner is a musician and actually has no clue what any of those strange symbols mean on his arm.”

That describes at least 90% of the ridership on the L-train at any given time. :)

http://www.facebook.com/profile.php?id=675806476 Drew Dominguez

I have the symbol of a transistor on my left arm. Which means I’m more or less stuck studying computer engineering now…

http://twitter.com/DoesitPew StacyD

Someone had a lot of fun with tube schematics at RadioMuseum…

JammitTimmaj had it pretty right.
It looks like it is purely power amplifier design (not a very strong one) and something which has more in common with home amplifiers of the 60’s than guitar amps. The only relative gain that the amp would provide would be what is native in the tube themselves…. not enough to rock the house (maybe some old school headphones or really low power horns?). It is just that guitar amps usually need massive gain and it looks like half of a weird headphone amp or something Webcor may have stirred up. This amp most likely has less than 10-15W (depending on tubes).
There are what seem to be other parts of the schematic on the arm, I would be interested in those.

Michael Colombo

No chance this would be the pre- section of a guitar amp, then going to the power amp? I can’t read the schematic myself but know that’s generally how guitar amps go about their business of making your ears bleed…

Michael Colombo

No chance this would be the pre- section of a guitar amp, then going to the power amp? I can’t read the schematic myself but know that’s generally how guitar amps go about their business of making your ears bleed…

http://twitter.com/DoesitPew StacyD

Nope. Look at the transformer used for the output. Jammit explained it pretty well. This could be a micro amp used for practice, but not for performance. The mu of those input tube would have to be over 50 to be useful at all. No tubes commonly used in guitar amps stand out at me. It looks like one of the simple example circuits at RadioMuseum.

michelle mailloux

i have a tattoo of a sleeve pattern on my arm, ive had it for years. a sleeve of a sleeve, i cant tell you how many times i get asked if its an electrical diagram. it would be the weirdest electrical diagram ive seen.

http://twitter.com/scowdich Scott

I have a CMOS-level NAND gate schematic on my arm. I know exactly what it means, and love explaining it to people who ask.

a tube amp! i have an entire book full of tube circuits. i keep holding on to it because i know it one of the few left of its kind. mostly RF, but some audio.

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

Anonymous

Gang,

Looks like the original Williamson Amplifier, well respected design. All octal tubes if I remember correctly.

Thanks
Wavelength

David Roy

Somehow this just does not seem like it would create a trend. Now maybe a Kat Von D with a schematic tatoo, that would bring it to a new level.

David Roy

Somehow this just does not seem like it would create a trend. Now maybe a Kat Von D with a schematic tatoo, that would bring it to a new level.

Anonymous

That could be an amp with power from 10 to 60 watts. It looks like one used in a Leslie Speaker from a Hammond Organ because it is missing a preamp.

If you’re a fan of Futurama on Comedy Central, you know they use schematics as robot porn. Go Bender, Go Bender . . .

http://pulse.yahoo.com/_BXT7S72GDGDFPWUA334PUF2M2U Mark

Jammit…. had it 99% right. 12AX7s have a mu of 100. I designed one just like it (except for a simpler phase splitter) over 50 years ago (all-in-one with speakers, etc.) using a pair of EL84s, and a couple of 7025s (lo-noise version of 12AX7). About 15 watts out, enough for a decent practice amp even back then with well-designed high-efficiency speakers. A few years ago I did the paper design for an updated version using HV FETs instead of tubes; still have the schematic and all the parts in my basement workshop! Also in the basement is a complete working 100 watt “practice amp” using a power OP AMP! That one dates back about 15 years…

http://pulse.yahoo.com/_7A7Q26SCPSTZFIUM5GVNWGMLEU Dougspair

…Well that certainly is a pretty close replica of a push-pull power amplifier like you might find in a Guitar amp Schematic…and yes…most were octal tubes…just heater, grids, cathodes and plates..

http://www.facebook.com/RFCafe Kirt Blattenberger

I put these pages together a couple years ago if you’d like to see more. There are a lot of nerd tattoo aficionados who actually do know what their artistry represents. With Michael’s permission, I’d like to add this one he took as well.

I’m getting an amp schematic tattoo soon. But it’s because I’m a qualified electrician. I don’t work as one anymore but it was an important part of my life. My Grandad is an electrician too and I’m going to ask him to design the circuit for the tattoo. An amp was my first ever project when I trained. And music is pretty good so it all ties together.